1. Field of the Invention
The present invention relates to a liquid supply system which utilizes a negative pressure to supply a liquid outside, and more concretely a liquid supply system in a liquid-jet recorder which prints or records characters on a recording medium by supplying a liquid to a recording head and a liquid supply vessel to be used in the liquid supply system.
2. Related Background Art
For a liquid supply method which utilizes a negative pressure to supply a liquid outside, for example, in a field of ink-jet recorders, there have conventionally been proposed and adopted ink tanks which apply negative pressures to ink discharge heads and configurations (head cartridges) in which the ink tanks can be integrated with recording heads. The head cartridges can be further classified into a configuration wherein the recording head is always integral with the ink tank (ink container), and another configuration wherein recording means and the ink container are separate from each other, can be separated from the recorder and are integrated for use.
A method which utilizes a capillary force of a porous material is mentioned as an easiest method to produce the negative pressure in such a liquid supply system. An ink tank which is used to carry out this method has a configuration which comprises a porous material such as a sponge accommodated, preferably in a compressed condition, to store ink entirely in the ink tank and an atmosphere communicating port which is capable of introducing air into the ink container for smoothing ink supply during printing.
However, a porous member which is used as an ink holding member poses a problem that the member lowers an ink accommodating efficiency per unit volume. In order to solve this problem, the applicant has proposed in EP0580433 specification an ink tank which has an ink container chamber substantially sealed as a whole except a communicated section from a negative pressure producing member chamber and is used in a condition where the negative pressure producing member chamber is open to atmosphere. Furthermore, the applicant has proposed in EP0581531 specification an invention which makes it possible to exchange the ink container chamber in the ink tank having the above described configuration.
The above described ink tank supplies ink from the ink container chamber into the negative pressure producing member chamber by a vapor-liquid exchange operation whereby the ink container chamber contains gas as the ink is discharged from the ink container chamber, thereby providing a merit that the ink is supplied under a nearly constant negative pressure during the vapor-liquid exchange operation.
On the other hand, the applicant has proposed in EP0738605 specification a liquid container vessel comprising a cabinet which has a substantial form of a prism, and a container which has outside surfaces identical or similar to inside surfaces of the cabinet and is deformable as an internally accommodated liquid is discharged, characterized in that the container is configured so that portions composing angles of the substantial form of the prism are thinner than center areas of the surfaces. This liquid container vessel allows the container to be adequately contracted as the liquid is discharged (a vapor is not exchanged for a liquid in a phenomenon), thereby being capable of supplying the liquid while utilizing a negative pressure. Accordingly, the liquid container vessel is free from a restriction imposed on a location of its installation as compared with a conventional bag like ink container member and can be disposed on a carriage. Furthermore, the invention allows ink to be held directly in the container and is excellent from a viewpoint to enhance an ink accommodating efficiency.
An ink tank of the above described type wherein a negative pressure producing member chamber and an ink container chamber are adjacent to each other causes a vapor-liquid exchange by introducing a gas into the ink container chamber at a stage to supply ink from the ink container chamber which has a predetermined or fixed accommodating space into the negative pressure producing member chamber.
When the ink is supplied from the ink container chamber into the negative pressure producing member chamber, external air is introduced in an amount corresponding to an amount of the supplied ink, whereby the ink and external air exist in the ink container chamber. The external air is swollen due to an environmental change (for example, a temperature difference within a day), whereby the ink may be introduced from the ink container chamber into the negative pressure producing member chamber. For this reason, there have conventionally been reserved in some cases a practically maximum buffer space in the negative pressure producing member taking into consideration a moving amount of the ink at a swollen ratio of the external air together with various environments of use.
Since the conventional vapor-liquid exchange operation allows atmosphere to be introduced by way of the communicated section as the ink is introduced from the ink container chamber into the negative pressure producing member chamber, the conventional vapor-liquid exchange operation is accompanied by a fear that the ink supply may be insufficient for abrupt consumption of the ink in the negative pressure producing member chamber in the case where the ink is to be supplied in a large amount in a short time from the negative pressure producing member chamber to an outside(a discharging head or the like).
The inventor et al. have already applied an ink supply system of a type which comprises the above described negative pressure producing member chamber and an ink container chamber which is adjacent to the negative pressure producing member chamber and allows the ink container chamber to be exchanged for the negative pressure producing member chamber, wherein the ink supply system is capable of reducing a buffer space in the negative pressure producing member chamber in various environments and supplying ink at a stable negative pressure during use of the ink container chamber while increasing a capacity for swelling of external air introduced by the vapor-liquid exchange, thereby being more excellent in practical utility, and the present invention has been achieved by a more preferable concept of the inventor et al.
In case of the above described exchangeable type ink container chamber, the ink tank which is repeatedly attached and detached is often equipped with a mechanism such as a valve to prevent ink from leaking while the ink tank is detached. In order to open the valve for attaching the ink tank in this case, a coupling section must have a stroke length in contrast to an ink container chamber which is not of the exchangeable type. However, experiments which were carried out by the inventor et al. have clarified a new problem that air bubbles remain and are accumulated in the coupling section dependently on a structure of a coupling section between the ink tank and the negative pressure producing member chamber in such a case where it is necessary to discharge a large amount of ink outside in a short time in particular.
The present invention has been conceived by the inventor et al. to solve the new technical problem described above, and has an object to provide an ink supply system which comprises a negative pressure producing member chamber and an ink container chamber which is adjacent to the negative pressure producing member chamber and the ink container chamber is exchangeable for the negative pressure producing member chamber, wherein the ink supply system is capable of supplying ink more stably as well as an ink tank to be used in the ink supply system.
Another object of the present invention is to apply the above described ink supply system to a liquid supply system having a configuration wherein an ink container chamber is always integrated with a negative pressure producing member chamber, thereby supplying ink more stably even in the liquid supply system which has a configuration described above.
Still another object of the present invention is to provide related inventions which have been achieved in solving the above described new technical problem.
In order to attain the above described objects, a liquid supply system according to the present invention is a liquid supply system which uses a liquid supply vessel which has a liquid container for accommodating a liquid in a sealed space, and a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid, has an atmosphere communicating port for communicating the negative pressure producing member with atmosphere and is capable of causing vapor-liquid exchange to discharge the liquid outside by introducing a gas into the liquid container by way of a section communicated with the above mentioned liquid supply vessel, characterized in that the above mentioned communicated section is disposed in a plurality and allows the vapor-liquid exchange.
A liquid supply system in another form of the present invention is a liquid supply system which uses a liquid supply vessel which has a liquid container for accommodating a liquid in a sealed space, and a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid, and has an atmosphere communicating port for communicating the negative pressure producing member with atmosphere and a section communicated with the above mentioned liquid supply vessel, characterized in that the communicated section is disposed in a plurality, the plurality of communicated sections are communicated with the liquid container of the liquid supply vessel, the liquid supply vessel can be separated from the negative pressure producing member containing vessel and the plurality of communicated sections have substantially equal heights.
Furthermore, a liquid supply system in still another form of the present invention is a liquid supply system which uses a liquid supply vessel which has a liquid container for accommodating a liquid in a sealed space, and a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid, and has an atmosphere communicating port for communicating the negative pressure producing member with atmosphere and a section communicated with the above mentioned liquid supply vessel, characterized in that the communicated section is disposed in a plurality, the plurality of communicated sections are communicated with liquid containers of separate liquid supply vessels and the liquid supply vessels can be separated from the negative pressure producing member containing vessel.
A liquid supply system in still another form of the present invention is a liquid supply system which uses a liquid supply vessel which has a liquid container for accommodating a liquid in a sealed space, and a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid, has an atmosphere communicating port for communicating the negative pressure producing member with atmosphere and a section communicated with the above mentioned liquid supply vessel, and is attachable to and detachable from the above mentioned liquid supply vessel, wherein the above mentioned liquid supply vessel is mounted above the negative pressure producing member containing vessel, characterized in that the communicated section is disposed in a plurality and the liquid container of the above mentioned liquid supply vessel can be separated from the negative pressure producing member containing vessel.
Furthermore, the present invention provides also a liquid supply vessel to be used in the liquid supply system described above.
A liquid supply vessel according to the present invention is a liquid supply vessel attachable to and detachable from a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid and has an atmosphere communicating port for communicating the negative pressure producing member with atmosphere, characterized in that the above mentioned liquid supply vessel has a plurality of apertures for communication with a plurality of communicated sections disposed in the above mentioned negative pressure producing member containing vessel and a liquid container which accommodates the liquid in a sealed space except the plurality of apertures, and that the plurality of apertures have substantially the same heights relative to a bottom in a condition of use.
Furthermore, a liquid supply vessel in another form of the present invention is a liquid supply vessel attachable to and detachable from a negative pressure producing member containing vessel which accommodates a negative pressure producing member capable of internally holding the above mentioned liquid and has an atmosphere communicating port for communicating the above mentioned negative pressure producing member with atmosphere, characterized in that the liquid supply vessel has a plurality of apertures for communication with a plurality of communicated sections disposed in the above mentioned negative pressure producing member containing vessel and a liquid container for accommodating the liquid in a sealed space except the plurality of apertures, and is mounted above the above mentioned negative pressure producing member containing vessel.
Since a plurality of communicating pipes are disposed in a negative pressure producing member chamber as joints to the liquid supply vessel according to the present invention, some of the communicating pipes can function normally even when air bubbles are accumulated in the other accumulated pipes and these pipes hinder ink from moving from the liquid supply vessel into the negative pressure producing member chamber, thereby making it possible to continue liquid supply. Furthermore, a vapor-liquid exchange operation is carried out positively in the joints which have relatively low resistance to ink out of the plurality of joints when the ink is supplied in a small amount from an ink supply port, whereas the vapor-liquid exchange operation is carried out in the plurality of joints when the ink is supplied in a large amount from the ink supply port. That is, the present invention makes it possible to feed a liquid stably from the liquid supply vessel into the negative pressure producing member chamber for high-speed printing or the like using a plurality of ink supply passages in conjunction with an ink supply speed to an outside.